This invention relates to consolidating or compacting apparatus in general and in particular to a machine for tamping or packing railway ballast, especially under and around crossties or sleepers, in order to provide a firm ballast for the track and for the rolling stock running thereon.
Vehicle-mounted tamping machines comprising pairs of cooperative tamping tools have been known and used extensively for compacting ballast laid in or forming a roadbed for a railway track. Driven into the ballast, each pair of tamping tools are vibrated and further oscillated toward and away from each other about horizontal axes extending in the transverse direction of the track, that is, in the longitudinal direction of the crosstie. This type of tamping machine has long had a problem in regard to its use as at the location of a railway switch or of guardrails laid alongside main rails as a safeguard against derailment. In the presence of such obstacles, the tamping tools cannot possibly be fed into the ballast if they are held in usual positions on the vehicle.
With a view to overcoming this problem, a tamping machine has been suggested wherein the spacing between the pairs of tamping tools is made adjustably variable in the transverse direction of the track. This known machine is still unsatisfactory, however, because the tamping tools displaced from their normal positions to avoid the above noted obstacles operate to tamp ballast some distance away from the loaded points of the crossite as they oscillate about horizontal axes extending in the transverse direction of the track.